DESCRIPTION: Analgesic-associated nephropathy is potentially fatal and costly yet completely preventable as a cause of renal dysfunction. Retrospective studies have reported an increased risk of renal dysfunction associated with consumption of large amounts of acetaminophen and nonsteroidal anti-inflammatory drugs (NSAIDs) but not aspirin. Since these analgesics are widely available and used, their association with renal dysfunction is particularly important. The primary objective of this study is to examine, prospectively, the association between chronic consumption of acetaminophen, aspirin and NSAIDs, and the risk of chronic renal dysfunction, defined as an increase in serum creatinine or a decrease in calculated creatinine clearance during the 5-year study period. From participants in two large female cohorts, the Nurses' Health Studies I and II (NHSI, NHSII), 3 groups of women will be identified, each comprised of 1150 participants (half from each cohort), who reported frequent use of acetaminophen, aspirin, or NSAIDs, and a fourth group of 1150 women who reported no use of these analgesics. Detailed information on dosage and duration of analgesic use will be obtained through supplementary questionnaires, to be mailed in the 01, 03, and 05 years, which have been shown to be reproducible. 4600 nurses will be enrolled at the outset and, after excluding women with prevalent renal disease and those who drop out, an expected 4000 will complete the study in the 05 year. The outcomes are: change in serum creatinine and calculated creatine clearance, measured at baseline and years 03 and 05 from all subjects. Mixed effects regression will be used to analyze the slope of renal function in the unexposed and exposed groups during the 5 year study period. For approximately 2000 subjects in NHSI, stored blood from 1989 will be used to perform the same analyses over a 13 year period. This study will provide: prospective data on change in renal function associated with chronic analgesic use; threshold levels of safe cumulative dose and duration of these analgesics; and population-based incidence rates and attributable risks of analgesic-associated chronic renal dysfunction.